Stomata and Lenticels

Stomata and Lenticels are two types of apertures in plants derived from the same embryological tissue. These structures are found on the surface of leaves, stems and young roots and allow gas exchange. Stomata (singular: stoma) are typically larger in size and cover more area than Lenticels as they have a greater need for carbon dioxide. Stomata decrease in number with age as plants require less CO2 to carry out photosynthesis.

What are Stomata?

Stomata are openings in the epidermal cells that allow the diffusion of gases within plants. The oval shape of stomata is a result of their being made up of stacked stacks of flattened cells called guard cells Stomata are found on leaves, stems and young roots. Stomata occur on all plant parts: in nature, the stoma is what gives them their green colour, but in agriculture there are many variations in colour for this reason. They are also located where leaves and roots join parts, but not at nodes or joints. On young leaves, there may be more than one opening per cell because two guard cells are formed from each cell.

Features of Stomata

Morphologically there are many features that may differ between stomata and lenticels. Stomata have an oval shape, with the long axis running in a horizontal line and the short axis horizontal or nearly so. Lenticels have a more spherical shape. The stomas are located on the outer surface of epidermal cells, but lenticels are found on the inner surface of cells. Stomata lack intercellular spaces and connect to neighbouring cells via narrow bases called rays. In contrast the lenticels are connected by the intercellular space. Stomata can be found on either the upper or lower surface of leaves, stems and young roots, while lenticels are circumscribed only to the surface of leaves. Stomata have pores called stomatal apertures through which CO2 and water vapour diffuse from outside to inside the plant. Water does not pass through stomatal pores but is mixed with it by osmosis.

What are Lenticels?

Lenticels are a type of aperture in plants produced by the same tissues that produce stomata. These small openings allow gas exchange between the outside and inside of the plant. Lenticels are found on the surface of leaves, stems and young roots where it occurs in clusters or scattered. They come in many different shapes, sizes and colours depending on the age of the plant. The significance of lenticels is that CO2 enters the plant through them; they are thus also used for measuring leaf age by counting the number on each leaf.

Features of Lenticels

Lenticels are made of the same intercellular forming tissue as stomata but lack a guard cell. They are considered to be part of the epidermis and their shape is rhombic or obovoid. The apex of an arrowhead from the short axis is at a distance greater than that from the long axis in stomata. The bases or rays of lenticels are thinner and longer than those of stomata. There are no pores through which water vapour penetrates into the leaf, but osmosis affects it as well since CO2 diffuses through both its surface and cellular wall.

Stomata and Lenticels: Differences

1. Stomata are larger than lenticels in size but are smaller in number than lenticels.
2. Stomata have a comb-shaped guard cell, which is bigger and thicker than that of the cell surrounding the stoma opening.
3. Stomata do not have intercellular spaces between them, but lenticels do.
4. The surface of the stoma is covered with cutin deposited by guard cells, but the surface of lenticels is covered with cutin deposited by epidermal cells. Both these effects appear on young leaves and may disappear on older ones.
5. Stomata are found on the outer surface of epidermal cells, but lenticels are found on the inner surface of cells.
6. Both have pores, but these are different in structure.
7. Water vapour is allowed to pass through stomatal pores into the plant, whereas there is no water vapour exchange with lenticel pores.
8. With a lack of osmosis and intercellular spaces between them, stomata are considered apertures that let gases in and out of the leaves.  Water is not passed through stomatal pores but by osmosis, it enters the leaf.

Conclusion

In conclusion it is clear that the relationship between the two structures is close. They are formed out of the same embryological tissue and arise at different times in the life of a plant. Stomatal development starts in young buds while lenticels start developing when young leaves emerge and may eventually disappear with age as they no longer serve as a respiratory route. Both stomata and lenticels are important for plant respiration; both serve to let gases into and out of the leaf. There is a difference between stoma and lenticel, but these structures have many similarities that help both plants in respiration.